MariaDB upgrade via the Plesk UI failed: The following package manager configuration files likely contain MariaDB repositories configuration which is not compatible with this upgrader

Symptoms

• The upgrade task of the MariaDB service via the Plesk UI failed with the error:

  PLESK_ERROR: The following package manager configuration files likely contain MariaDB repositories configuration which is not compatible with this upgrader:
  /etc/yum.repos.d/MariaDB.repo To proceed with the upgrade, comment out or remove these repositories related to MariaDB.

Cause

The server contains the MariaDB repository of the old version or contains invalid configuration. 

Resolution

Move the old repository file to another location using the following steps:

1. Connect to the server via SSH;

2. Move out the reported repository file:

# mv /etc/yum.repos.d/MariaDB.repo /root/

3. Start the upgrade process again.